A friend of mine recently bought a fancy new MacBook Air. He struggled with paying the "Apple tax," but decided the razor-thin laptop was worth the $1799 price tag. Then, about a month later, he made a startling discovery: Apple was selling refurbished Airs for just $999. Had he poked around the company's online store instead of giving in to retail temptation, he could have been $800 richer.

I don't like it when shoppers pay more than they need to. And given the economy's parlous state, we all need to be careful with our tech dollars. So it's a good time for a refresher course in the tricks of the cheapskate trade.

This isn't chump change I'm talking about; over the course of a year, the 31 tips in this series (see the list below) could save you more than $7500. Granted, that figure is based on my ballpark estimates, and I'm a fairly heavy shopper (rarely does a week or two go by without my ordering something). Your results will likely be different--but should still amount to some serious money.